THE MECHANICS OF STAMPS PRODUCTION

BY: - F. Aleem Sundal

Stamps are not always printed on paper. Also they are not always gummed. In Iran, postage has been printed on gold foil without gum and perforation but in Colour. There are even examples of stamps printed in 24 carat gold (Pakistan). Many other countries have produced stamps with varied amounts of gold and silver. Self-adhesive and three dimension stamps are becoming popular in Arab States and in Europe.

SHAPES Stamps are produced almost in all possible geometrical shapes – circular, hexagon, and octagon, parallelogram, triangular, square and rectangular. They have taken the shapes of medallions, country maps, human figures and even fruit like bananas and watermelons. But these are exceptions and are not much popular among serious collectors, because of their restricted nature.

PAPER Many of the early stamps were printed on hand made watermarked paper in sheets of required size. But most of the later issues are printed on machine-made paper in continuous rolls. Naturally early stamps had greater variations in paper quality.

There are many kinds of paper used for stamps, e.g., Laid paper, Quadrille paper, Granite paper, Toned paper, Manila paper and Silk Threaded paper, Shortage of paper in wartime, saw the printing of postage stamps on currency note paper, on newsprint and on the backs of poster size maps. These prints are of immense philatelic interest. The three most commonly used types of paper are:

ORDINARY WOVE PAPER  Most of the stamps are printed on wove paper, having a plain, even texture, created when pulp is brought in contact with the finely netted wire mesh of the papermaking machine.

In developing countries this type of paper is generally used for commemorative stamps, as it is comparatively cheaper and suitable for short-lived items in limited quantity. It can easily be distinguished from its printed surface, which is somewhat coarse and printing not very sharp.

CHALK SURFACED PAPER This paper is coated with a chalky solution and has a glossy effect and is most commonly used for security documents, especially stamps. Chalky paper may be distinguished by a simple test. If touched with silver, a kind of pencil mark is caused but it can spoil the stamp. Printing on chalky paper is very sensitive and the stamp is likely to be ruined when introduced to water.

PHOSPHORIZED PAPER This is the most recent addition to paper qualities and is extensively used in European countries where automatic letter sorting machines are employed. The prime purpose of phosphor is to respond to electronic signals from machine sensors for detection and separation of classes of mail and also to evaluate the postage being paid.

PERFORATION A series of holes is punched around stamps for separation. The number of holes in each linear inch of any side of a stamp is called its perforation. Sometimes compound perforation is punched on a single stamp, for example, if perforation is described as, p14 x 15, it means that the stamp has 14 holes at the top and bottom and 15 each on both sides.

Perforating machines are of two types and punch holes in two distinct manners called comb and line perforation. Perforation pins are arranged in the form of a “comb”. Vertical and horizontal rows are perforated at a time and are identified by the evenness and regularity of the intersecting holes. But in line perforation, rows of stamps are punched in single lines, either vertical of horizontal. The sheet is then turned sideways on and the process repeated. Line perforation can usually be identified by the fact that the intersecting holes at the corners of stamps never match precisely.

Many types and shapes of perforation are used in stamp making. Round whole perforation has two varieties. Holes of two or more different diameters are placed in a row like “comb”.

But a quite different type of perforation is rouletting. Roulette is a French word, meaning a tool with toothed disc or wheel for perforation of paper. It makes in a sheet of paper, pin shaped, arc-shaped, tiny cross-shaped, zigzag or straight cuts, but no portion of paper is removed.

Among roulette perforation, the serpent roulette is most significant. Here cuts in the form of wavy lines are made between the stamps and great care is required in separating them. All these methods were not successful and Europe in the 19^th century. Asian countries, however, used this system till as the 1960’s.

GUM This is the adhesive substance usually applied on the back of stamps for pasting them on letters. Occasionally stamps are not gummed for various reasons. In the nineteenth century tree gum was used which cracked after a few months if not used. Cracking also breaks the stamp itself. Often bacteria consume the entire gum.

These days, two types of gum are universally used. Polyvinyl alcohol (PVA) is most common in Pakistan as well as in other countries. It is somewhat glossy and Colour-less, because of the presence of alcohol in it, this kind of gum is being replaced with Gum Arabic (GA) and the recent Pakistan stamps are gummed with it. Gum Arabic also so Colour-less that it cannot be distinguished if a stamp is gummed. Since 1973, a substance called dextrin is added to PVA. The mixture appears bluish green and is called PVAD.